It is sufficiently well known from the prior art that the genetic origin and functional activity of a cell can be determined and investigated by studying its nucleic acids. The analyses of the nucleic acids and proteins provide direct access to the cause of cell activities. They are thus potentially superior to indirect conventional methods such as, for example, the detection of metabolic products. Thus, molecular biological analyses are already used in many fields, e.g. in medical and clinical diagnostics, in the pharmaceutical field in the development and evaluation of pharmaceutical compositions, in food analysis and also in monitoring food production, in agriculture in the cultivation of crops and farm animals as well as in environmental analysis and numerous fields of research.
By analysing the RNA, particularly the mRNA in cells, it is possible to determine the activities of genes directly. The quantitative analysis of transcription patterns (mRNA patterns) in cells by modern methods of molecular biology, such as e.g. Real time Reverse Transcriptase PCR or gene expression chip analyses makes it possible for example to detect wrongly expressed genes, thereby detecting metabolic disorders, infections or the development of cancer. The analysis of the DNA from cells by molecular biological methods such as e.g. PCR, RFLP, AFLP, SNP or sequencing makes it possible for example to detect genetic defects or to determine the HLA type and other genetic markers.
The analysis of genomic DNA and RNA is also used for directly detecting infectious pathogens such as viruses, bacteria etc.
It is an absolute prerequisite for nucleic acid analysis to stabilise the nucleic acids and proteins immediately after the biological sample has been taken from its natural environment. This applies to DNA and particularly RNA, which can be broken down very rapidly after the biological sample has been taken. On the other hand, once the biological sample has been taken, new mRNA molecules may be synthesized by the induction of stress genes, for example, thereby changing the transcription pattern of the cells. This can falsify subsequent analysis. In the medical field in particular it is essential to stabilise nucleic acids as it is common in practice for samples containing nucleic acids to be taken and then not investigated further until they have first been stored for some time and transported to a laboratory.
In the meantime, the nucleic acids contained in the samples can change or even break down completely. This naturally has a massive influence on the results of any tests carried out subsequently or makes them completely impossible. Such tests are carried out using molecular biological techniques such as, for example, Northern and Southern Blot Analysis, PCR, RT-PCR, SunRise, LCR, branched DNA (bDNA), SDA, DNA and RNA chips and arrays for gene expression and mutation analysis, RFLP, AFLP, SNP Analysis, cDNA Synthesis, subtractive hybridisation or Taqman technology and other real time quantifying methods. On the other hand, the use of highly purified intact nucleic acid—DNA or RNA—constitutes a criterion of fundamental relevance for the use or carrying out of the above mentioned tests. In addition, the isolation of the samples containing nucleic acid and the assays also constitutes a time consuming operation. Moreover, contamination of an investigating laboratory working in the field of molecular biology—such as may occur for example if a test goes wrong—may lead to erroneous test results.